Improper Handling of Windows Device Names The advisory has been revoked - it doesn't affect any version of package open-webui (opens in a new tab)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CHAINGUARDLATEST-OPENWEBUI-14913880
- published13 Jan 2026
- disclosed8 Jan 2026
Introduced: 8 Jan 2026
CVE-2026-21860 (opens in a new tab)Amendment
The Chainguard security team deemed this advisory irrelevant for Chainguard:latest.
NVD Description
Note: Versions mentioned in the description apply only to the upstream open-webui package and not the open-webui package as distributed by Chainguard.
Werkzeug is a comprehensive WSGI web application library. Prior to version 3.1.5, Werkzeug's safe_join function allows path segments with Windows device names that have file extensions or trailing spaces. On Windows, there are special device names such as CON, AUX, etc that are implicitly present and readable in every directory. Windows still accepts them with any file extension, such as CON.txt, or trailing spaces such as CON. This issue has been patched in version 3.1.5.